. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA 413 (0 0) *^ 'V) o E 3. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Juvenile : adult ratio Fig. 24. Histogram of juvenile : adult ratios in samples containing > 100 specimens. Brouwers 1988). In contrast, 39 per cent of the sites have juvenile: adult ratios that indicate some post-mortem disturbance, and the majority of these (29% of the total) suggest removal of instars, presumably by currents. The problem with this type of approach is that the instars of large
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. QUATERNARY OSTRACODS FROM SOUTH-WESTERN AFRICA 413 (0 0) *^ 'V) o E 3. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Juvenile : adult ratio Fig. 24. Histogram of juvenile : adult ratios in samples containing > 100 specimens. Brouwers 1988). In contrast, 39 per cent of the sites have juvenile: adult ratios that indicate some post-mortem disturbance, and the majority of these (29% of the total) suggest removal of instars, presumably by currents. The problem with this type of approach is that the instars of larger species are larger than adults of some smaller taxa, and that methods relying on the juvenile : adult ratio or a detailed population age structure, using all the various instar stages ( Whatley 1988), take no account of size differences between species. Nevertheless, the results have been presented for comparative purposes, and possible implications for sea-floor conditions will be mentioned further in the discussion section. BARREN SAMPLES In understanding the distribution of the ostracod assemblages, a knowledge of the environments in which they are not found is almost as important as knowing the circumstances under which they do occur. Of the 270 samples examined for ostracods, a surprisingly large number (81; ) were barren. These sites extend from west of the Cape Peninsula to just south of the Kunene River (Fig. 25) but are concentrated in two main inner~mid-shelf areas: north and south of the Orange River, and in deep water. In detail (Fig. 26), both shelf areas are further subdivided: a small cluster of sites occurs west of the Cape Peninsula between 200 m and 300 m, separated from the Namaqualand inner-shelf zone, whereas the extensive northern zone, which becomes progressively deeper south of Walvis Bay, is. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance o
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
